Brake adjustment



June 15, 1937. HOUSE 2,083,651

BRAKE ADJ US TMENT Filed Aug. 14, 1935 Patented June 15, 1937 UNITEDSTATES PATENT OFFICE BRAKE ADJUSTMENT Gilbert K. House, Dayton, Ohio,assignor to General Motors Corporation, Detroit, Mich, a corporation ofDelaware Application August 14, 1935, Serlal No. 36,100

2Claims.

- of the shoes of an internal brake.

Other objects and advantages will be understood from the followingdescription. In the accompanying drawing: Fig. 1 is a vertical sectionthrough a brake drum showing my novel adjustment means for the shoes.

Fig. 2 is a section on line 2-2 of Fig. 1. Fig. 3 is a perspective of adetail. Fig. 4 is a plan view, partly in section, of a modified form.

Referring to the drawing, numeral 5 designates a brake drum to becarried by a vehicle wheel as usual. To fixed anchor plate 1 are pivotedat 9 articulating links H and I3. At I5 and I1 these links are pivotedto drum engaging shoes l9 and 2|. The shoes have linings 23. To anchorplate 1 is secured by fastening means a wheel cylinder 21 of a hydraulic.brake system. Within the wheel ,cylinder are pistons 29 with packing3|. 25 A spring 33 is located between the pistons to hol'd'packing 3|against pistons .29, and suitable hydraulic medium from a conventionalmaster cylinder enters at 35. Slidable within each end of the cylinderis a plunger 31 of cup shape, its head 39 engaging the similarly shapedhead 4| of an outer cup 43 slidably engaging the wall of the cylinder21. The two cups 43 engage the adjacent ends of the two shoes and spreadthem apart when the pistons are separated by the introduction of fluidmedium through opening 35. Adjustably mounted on the cover or fixedplate] 1 is a stop device 45 shown best by Fig. 3. This device has aflat part 41 lying against the fixed plate I. This fiat part 41 has abent up end 49, 40 an elongated opening 5| and a tongue 53, the latterturned up from the material of the part 41 into parallelism with end 49.A substantially right angledpart 54 is cut away to form an arc 51. Webs59 unite the two parts. The dimen- 45 sions are such that while part 41lies against the fixed plate 1 the arcuate surface 51 will lie againstthe circumferential wall of the cylinder as shown by Fig. 2. The cup 43may slide along the cylinder wall. When retracted, it engages the partor wall 54 adjacent the arcuate surface 51. The walls 54 of the twoparts 45 serve, therefore, to limit the release position of the cups 43and, therefore, of the brake shoes when drawn to their position ofrelease by spring means 59, 6|.

55 As the shoe lining 23 becomes worn it is necessary to adjustoutwardly the stops 45 so that the cups 43 engage the stops in newpositions of the latter axially of the cylinder. Through a circular holein the plate 1 and through the elongated opening 5| of the stop deviceis a pin 63 carrying an eccentric 65 located between the end 49 andtongue 53. As the pin is turned by using a suitable tool on its head 55,the eccentric rotates and pushes member 45 to provide a new stopposition for the cups 43 and therefore for the brake shoes. Numeral 56is a lock nut to hold the eccentric 65 in positions of adjustment.

Fig. 4 shows a modified form. In this form the pistons 61 are ofinverted cup shapeand are provided with packing 3|. A spring 33 is usedas before. The open ends of the cup-shaped pistons 61 engage the bottomwalls of cups 69. To the bottom walls of each cup 69 is secured, as byriveting, a stem 1|, bifurcated at 13, to engage the adjacent brake shoel9 or 2|.

To the, inside open end of each cup 69 is threaded an angular member 15,one face of which carries screw threads and the other face of whichengages a shoulder 11 formed on the cylinder 21'. Teeth 19 on the member15 are accessible by removal of a cover 8| from over an opening 83 inthe fixed plate 1. The limiting inward position of the cups 69 and ofthe shoes is determined by the engagement of the angular part 15 withthe shoulder. Adjustment of the cup 69 relative to member 15 changes therelease position of the shoes.

In both forms the cylinder has been shown as having pistonshydraulically applied. It will be understood that cam means of any knowntype may be substituted as the instrumentality for spreading the pistons29 or 61, in which case similar provision for adjustment may beemployed.

I claim:

1. In combination, a drum, a cover plate, shoe means to frictionallyengage said drum, reciprocable means to engage and move said shoe means,movable means adapted to engage and move said reciprocable means, and anadjustable member supported on said cover plate and adapted to beengaged by said reciprocable means to determine the release position ofsaid shoe means, said adjustable member having opposed lugs, a discbetween said lugs and a bolt eccentrically secured to said disc, andmeans to secure said bolt in positions of adjusted rotation to saidcover plate.

2. In combination, a drum, a cover plate, shoe means within the drum, 9.wheel cylinder, a plunger therein, a cup reciprocable upon the end ofthe cylinder, engaged by the plunger and adapted to engage and move theshoe, an angular member having one face adjustably secured to the coverplate and its other face positioned GILBERT K. HOUSE. I

